My cruise control on my 2003 Chevy Trailblazer also doesn't work...any ideas why or how to fix it? PLEASE HELP

Check the rear brake lights, if they are out you probably have a bad brake switch. Replace the brake switch on the back of the brake pedal.
Check all the fuses. Make sure the bulbs are correct.
If other lights such as the ABS light illuminates, look towards an ignition switch. There is a service bulletin on this issue.